Apparatus for forming metallic sheet members



R. E. ROPER 3,254,521

APPARATUS FOR FORMING METALLIC vSHEET MEMBERS June 7, 1966 5Sheets-Sheet 1 Original Filed Feb. 23, 1962 Fig. 1.

RM EU AH'orn 95 R. E. RoPER 3,254,521

APPARATUS FOR FORMING METALLIC SHEET MEMBERS June 7, 1966 5 Sheets-Sheet2 Original Filed Feb. 23, 1962 INVENTOR. RALPH E. RoPER BY ;/W/z,.wfaw

AHo vn cys Fig. a.

June 7, 1966 R. E. ROPER 3,254,521

APPARATUS FOR FORMING METALLIC SHEET MEMBERS 5 Sheets-Sheet 5 OriginalFiled Feb. 25. 1962 Fig. 5.

June 7, 1966 R. E. RoPER 3,254,521

APPARATUS FOR FORMING METALLIC SHEET MEMBERS original Filed Feb. 2:5.1962 5 sheets-sheet 4 o INVENTOR. Flg. 7 RALPH E. Roman AHorneys June 7,1966 R. E. RoPER 3,254,521

APPARATUS FOR FORMING METALLIC SHEET MEMBERS Original Filed Feb. 25,1962 5 Sheets-Sheet 5 9 unv Il! l lll/11111111 INVENTOR RALPH E. RoPERBY Mmwfw AH'orneyS United States Patent O 3,254,521 APPARATUS FORFORMING METALLIC SHEET MEMBERS Ralph E. Roper, Indianapolis, Ind.,assignor to Wallace Expanding Machines, lne., Indianapolis, Ind., acorporation of Indiana Original application Feb. 23, 1962, Ser. No.175,152, now Patent No. 3,222,910, dated Dec. 14, 1965. Divided and thisapplication Feb. 11, 1965, Ser. No. 438,156

This application is a division of application, Serial No. 175,152, filedFebruary 23, 1962, now Patent No. 3,222,- 910, issued December 14, 1965.

The present invention relates to apparatus for forming metallic sheetinto parts such. as :automobile fenders, doors, bonnets and other drawnsheet metal parts.

It is conventional practice in the automobile industry to draw fenders,doors and in fact practically all sheet metal parts of this type by theuse of toggle presses. These toggle presses usually operate to grip a atsheet of metal around and adjacent the edge thereof. The sheet is thenformed inwardly of the gripped edge thereof by the use of cooperatingmale and female dies. Many Vproblems are involved in drawing metal inthis manner. First, it is frequently necessary to ovedraw a part inorder that it have the correct final shape. The amount of overdrawingnecessary can only be an educated guess which must be made by one havinglong experience in the iield. Even then the .final product isunpredictable and may be far outside the desired tolerances.

Second, the toggle press is usually the weak link in the formingprocess. In practically all production lines, the various otherapparatus such as trimming and ilanging devices and the like must waiton the toggle press which paces the production line. Also, the togglepress is usually capable of forming only a single lshape or part at onetime and consequently, long expensive down time is experienced duringwhich the toggle press is converted over from one part tov another. Forexample, the toggle press might be operated to produce left-handautomobile doors for a period of time and then converted over toright-hand automobile doors. It will be evident that thisv situationalso results in storage problems of the one type of part which has beenmost recently formed and alsocauses diculties in production planning.

Consequently, a primary object of the present invention is to provideimproved apparatus for forming metallic sheet material into parts.

A further object of the present invention is to provide apparatus forsheet metal forming which, as compared to toggle presses,r drasticallyreduces scrap, greatly increases structural strength, permits the use oflighter gauge metal and reduces tooling costs.

Another object of the present invention is to provide apparatus forsheet metal forming which, as compared to toggle presses, drasticallyreduces initial cost.

Still another object of the invention is to provide apparatus for sheetmetal forming which, as compared to togglev presses,v increases speed ofproduction, reduces the amount of metal finishing required and makespossible greater exibility in the shapes that can be formed.

Related advantages o'f the invention are that it makes possible..precise forming of parts Without guesswork and makes possible theforming of a plurality of parts simultaneously, thus reducing storagespace necessary and alsoA reducing loss of production time in toolingchange-over.

Related objects and advantages will become apparent as the descriptionproceeds.

One embodiment of the method of the present invention comprises thesteps of bending a sheet of metal into a closed shape with the oppositeedges thereof in engage- 3,254,521 Patented June '7, 1966 ice ment,securing the opposite edges together, expanding and stretching theclosed shape over a die structure baving a discontinuous forming facewherein each continuous portion of the forming face defines one completesurface of a respective one of said parts and cutting the metal betweenthe thus formed parts to separate them.

One embodiment of the apparatus of the present invention comprises aplurality of dies each having an outwardly facing surface which has theshape desired for one complete surface of a respective one of the parts,means for simultaneously moving the dies radially outwardly to stretchan annular sheet metal member thereover and to form the parts, and meansflor separating the thus formed parts.

The full nature of the invention will be understood from theaccompanying drawings and the following description and claims.

FIG. 1 .is a top plan view of an expander forming a part of the presentinvention.

FIG. 2 is a perspective view of a closed sheet metal rlplember preformedfor reception within the expander of FIG. 3 is a vertical section takenalong the line 3-3 of FIG. l in the direction of the arrows.

FIG. 4 is a top plan view similar to FIG. 1 but showing the parts indifferent operating position.

FIG. 5 is a vertical section taken along the line 5-5 of FIG. 4 in thedirection of the arrows.

FIG. 6 is a top plan view of apparatus for performing the method of thepresent invention.

FIG. 7 is an enlarged vertical elevational view taken generally alongthe line 7-7 of FIG. 6l and showing barrel forming and preformingapparatus forming a part of the present invention.

FIG. 8 is a fragmentary vertical section through cutting apparatusforming a part of the present invention and taken generally along thelline 8-8 of FIG. 6.

FIG. 9 is a fragmentary horizontal section taken along the line 9 9 ofFIG. 8 in the direction of the arrows but showing the device in adifferent operating position. Referring now more particularly to thedrawings, there is illustrated in detail in FIGS. 1, 3, 4 and 5 anexpander apparatus 9 which operates upon the rectangular shaped closedsheet metal structure shown in FIG. 2 to expand it intoa cluster ofconnected sheet metal parts. The expander includes a base 10 Which issupported upon vertically extending members 11 and has ixed thereto acylindrical or ring-shaped vmember 12. In order to r-rnly fix thering-shaped member to the base, the member 12 is provided with adownwardly projecting annular lip 15 which is received within a suitableannular recess 16 in the base. An annular top plate 17 is fixed to theupper edge of the ring-shaped member 12 in similar fashion with lip 18in recess 19 whereby a rigid cylindrical housing 20 is provided. Toprovide an even further amount of strength and rigidity, four shoulderedvertical pins 21 are received within suitable apertures in the base andtop plate and x these members in spaced relation.

lA plurality of radially extending keys 22 are fixed to and receivedwithin suitable radially extending apertures in the base 10. The keys 22provide trackways for four tool or die carrier members 25 and 26. Fixedt-o the outer faces of the carriers 25 and 26 are scab dies 27 and 28which can be removed and replaced by different shaped dies if desireddepending upon the .type of part being formed. The dies and diecarriersv 25-28 are movable between `the base 10 and a center clustertop plate 30 which is fixed in spaced relation to the base 10 by meansof shouldered bolts 31, the top plate 30 acting to retain the diecarriers upon the trackway forming keys 22.

Each of the die carriers and 26 has a tapered inner surface 32 and 33against which the tapered outer surfaces 35 and 36 of an inner drivemember 37 act. The driver member 37 is fixed to a vertically extendingpiston rod 40 of a iiuid motor 41 which is fixed to the base 10. Whenthe motor 41 is operated to move the driver 37 downwardly, the surfaces35 and 36 of the member camagainst the inner surfaces 32 and 33 of thedie carriers to move them outwardly. When the fluid motor 41 is operatedto move the piston rod 40 and driver member 37 upwardly, the diecarriers 25 and 26 are drawn inwardly by means of T-shaped keys 42 and43 (FIG. 3) fixed to the surfaces 35 and 36 and received within T-shaped slots 45 and 46 (FIG. 4) formed within the die carriers. Thus, itcan be appreciated that vertical move- -ment of the driver member 37 inopposite directions produces inward and outward movement of the diecarriers 25 and 26 and the dies 27 and 28 mounted thereon.

The surfaces 32 are tapered at a different and greater 'angle to thevertical than the surfaces 33. Thus, when the driver member 37 is movedto its uppermost position as shown in FIGS. 1 and 3, the dies 27 aremoved a greater amount radially inwardly than are the dies 28. Each ofthe dies 28 is formed with a recess 47 in its rearward face whichreceives the end portion of each of the dies 27. When the dies 27 and 28are moved to their outward position by the driver member 37, the dies 27travel a greater radial distance than do the dies 28. By the abovedescribed arrangement, the circumference of the inner dies, when intheir innermost position, can be made smaller without reducing thedistance (taken horizontally) across the forming faces 51 and 52 ofthose dies.

Four outer die carriers 55 are radially slidable along thetrackway-providing keys 22. Preferably, bearings 23 formed of bronzematerial or the like, are provided in the base 10 at its upper surfaceacross which the die carriers 55 and 26 and 27 travel. Each of the diecarriers 55 has an outer die 56 mounted thereon. The outer dies 56 areprovided with inwardly projecting portions 57 which function to form theindentations and recesses in the external surfaces of the cluster ofparts being formed in the work piece 60.

The annular top plate 17 has fixed in the lower face thereofradially-extending keys 61 which project into upwardly-opening grooves62 in the upper surface of the outer die carriers 55 and act asadditional trackways for the die carriers 55. The outer die carriers aremoved inwardly and outwardly by means of cam means 65 which may be inthe form of a ring. The cam ring 65 is provided with tapered inwardlyfacing cam surfaces 66 which act against cooperating surfaces 67 o'n theexternal faces of the outer die carriers 55. A plurality of fluidcylinders 68 are xed to the base 10 and have their piston rods 69 fixedto the cam ring 65 whereby upward projection of the piston rods causesythe cam surfaces 66 to move across the surfaces 67 of the outer diecarriers and to move the outer die carriers radially inwardly. Theinner- `most position of the die carriers 55 is shown in FIG. 5.

In this position, the vertical surfaces 70 of the cam ring 65 are inengagement with the vertical surfaces 71 of the outer die carriers.Consequently, further vertical movement and seating of the cam ring 65against the top plate 17 produces no corresponding radial movement ofthe die carriers and the die carriers are locked in the illustratedinward position by the surfaces 70 and 71.

Each of the forming faces 51 and 52 of the dies 27 and 28 defines thedesired shape of the complete inner surface of a respective one of theparts to be formed from the work piece 60. In the illustratedembodiment, four automobile door panels are to be formed from the closedsheet metal work piece 60. Referring to FIG. 4, these four desiredshapes are shown at 75, 76, 77 and 78 and are connected by scrap metalportions 79.

In order to form the cluster of parts shown in FIG. 4, the rectangularwork piece 60 is placed about the dies 27 and 28 in the position show-nin FIG. 1 with the dies all drawn to their innermost position byprojection of the piston 40 and driver member 37 to their uppermostposition as shown in FIG. 3. The outer cam ring 65 is then moved fromthe position of FIG. 3 to the position of FIG. 5 by projection of thepiston rods 69 of the cylinders 68. The driver member 37 is then moveddownwardly to the position of FIG. 5 causing the dies 27 and 28 to moveoutwardly and to stretch the metal'of the workpiece 60 thereover.Because of the fact that there are no binders or devices gripping any ofthe metal of the workpiece, it is free to ow uniformly and to stretchout not only over the forming faces of the dies 27 and 28 but also atthe scrap portions 79 whereby the nal transverse dimension takenhorizontally across the parts -78 is greater than the complete initialcircumference of the workpiece 60 as shown in FIG. 2. It should bementioned that the horizontal cross section of the final parts 75-78 isnot necessarily constant and in most cases (for example, in formingfenders) varies greatly from Ithe top of the parts to the bottomthereof. Thus, the metal ows andstretches not only horizontally but alsovertically.

As the dies 27 and 28 move outwardly, they engage the outer dies 56 andcause the projections 57 of the outer dies to force against theworkpiece 60 and to produce the desired indentations and recesses in theexternal surface of the parts 75-78. The final forming position oftheapparatus is shown in FIG. 4. It can be appreciated that until the innerand outer dies are fully engaged, the metal is free to flow and stretchand there are n0 binders or members gripping the work piece andpreventing free ow.

The outer dies are then moved outwardly to their original position bydownward movement of the cam ring 65. The cam ring has mounted thereon aplurality of T-shaped keys 80 which lare receivable within T-shapedslots 81 in the external surface of the die carriers 5,5. As the camring moves downwardly, the keys 80 move into the slots 81 and camagainst the surfaces 82 of the louter dies causing the outer dies to bemoved outwardly away from the work piece and to return to the positionshown in FIGS. 1 and 3. The driver member 37 is raised upwardly byprojection of the piston rod 40 causing the die carriers 25 and 26 andthe dies 27 and 28 to be moved inwardly and to return Ito the positionillustrated in FIGS. 1 and 3.

It should be noted that the parts 75 and 77 are allochirally related tothe parts 76 and 79. In the illustrated embodiment of the invention, theparts 75 and 77 may be identical left-hand automobile doors yand theparts 76 and 78 identical right-hand automobile doors. Because suchallochirally related parts have the same vetrical dimension and similarshapes, the present invention is particularly adapted for forming suchparts. This is true because the amount of metal needed and the amount ofdrawing needed for each such part around the workpiece is equal. Thus,an inexpensive and easily constructed workpiece of constant axial lengthis used in the present embodiment.

Fixed to the base 10 is a plurality of fluid cylinders 85 having .pistonrods 86 with pads'87 on the distal ends thereof. The fluid motors arethen operated to project theirV piston rods and raise the feet 87 tolift theformed workpiece upwardly out of the apparatus. The workpiece isthen picked up by automatic transfer means and carried to furtherapparatus which cuts the workpiece along the scrap portion area 79 -toseparate the parts. lhis further cutting apparatus is described indetail be- Referring to FIG. 6, the complete system for practicing themethod of the present invention is illustrated schematically. Aconventional barrel forming and welding machine 90 functions to convertstrips of sheet metal into sheet metal cylinders of a desired diameter.The machine 90 bends the :sheet metal until the opposite edges thereofengage and then welds the opposite edges together to form the desiredcylindrical shape. A suitable machine of this type for use in thepresent invention is Special Appliance Type barrel Welder manufacturedby Federal-Warco Division of McKay Machine Co., Warren, Ohio.Alternatively, this welded cylindrical workpiece could be manufacturedmanually by manually bending a rectangular sheet of metal until theopposite edges engage, welding the edges together and grinding down theweld in a conventional manner so that the thickness of the weldedportion is equal to the thickness of the sheet metal.

After the machine 90 has formed the sheet metal into the desired weldedcylindrical workpiece, the cylindrical workpiece is moved by the machine90 onto "an expander 91 forming a part of preforming apparatus 92. Asshown in dotted lines in FIG. 7, the expander 91 may be tilted to aposition wherein the axis of the expander 91 extends horizontally sothat the cylindrical workpiece can be placed thereover by machine 90.

The preformer 92 includes a base 95 including vertical posts 96 andhorizontal members 97 fixed to and connecting the posts 96. A table 100is pivoted upon the base 95v at 101. Four dies 102 are horizontallyslidable upon the upper `surface of the table 100 and are guided forradial movement by guide members 103. Each ofv the dies 102 is providedwith 4a pair of the guide members 103, each of which is fixed to thetable 100 and has an inwardly projecting portion 105 received within ahorizon- I the dies 102. A driver member 106 having a cross-shaped crosssection is received within the dies 102 and .is keyed thereto byT-shaped keys 107 in the manner described above with respect to theexpander of FIGS. 1, and 3-5. Similarly to the above described expander,the driver 106 and dies have cooperating tapering cam surfaces 108 and109. Thus, vertical movement of the driver 106 in opposite directionsproduces inward and outward movement of the dies 102. Axial movement ofthe driver member 106 is effected by cylinder motor 110 4fixed to thetable 100 and having its piston 111 fixed to the driver member.

A tilt cylinder motor 112 is pivoted to the horizontal members 97 andhas its piston rod 115 pivoted to the table 100. The tilt cylinder 112functions to move the table 100 between the solid line position and thedotted line position of FIG. 7. As mentioned, when the expander 91 is inthe dotted line position, the cylindrical work piece is received.thereon from the machine 90, the expander 92 is then moved to the solidline position wherein the cylinder seats itself against the table 100.The cylinder 110 is then operated to move the driver member 106downwardly and to expand the dies 102 preforming the cylindrical workpiece into the rectanguiar workpiece shape 60 shown in FIG. 2. Theworkpiece is then removed lfrom the expander 91 by returning the driver106 of the expander to the upward illustrated solid line position and bysuitable automatic transfer apparatus 115. This automatic transferapparatus functions to transport the workpiece 60 to and into theexpander 9 of FIGS. l and 3-5 where the above described formingoperations take place. As an alternative to the above described barrelforming machine 90 and preformer 92, the rectangular Vworkpiece of FIG.2 might be formed and Welded by a single machine. This alternative isespecially desirable where the workpiece is relatively large.

The rectangular workpiece is then expanded to the shape shown in FIG. 4by means of the expander apparatus 9 and as above described inconnection with FIGS. 1 and 3 5. The expanded workpiece is then liftedout of the expander 9 by means of the fiuid cylinders 85 and istransported by automatic transfer apparatus 116 to a splitter apparatus117 shown schematically in FIG. 6 and in greater detail in FIGS. 8 and9. The function of the splitter apparatus 117 is to separate the variousparts formed in the expanded workpiece from one another. In the presentembodiment,`the splitter apparatus separates the parts 75-78 by a singlecut through each of the scrap portions 79. The four resulting parts arethen conveyed along conventional conveyors 120 to suitable conventionaltrimmer die apparatus which function to trim the remaining portions ofthe scrap 79 from the individual parts 75-78; Alternatively, thesplitter apparatus 117 may be designed so as to complete this trimmingfunction in a single operation.

Referring more particularly 4to FIGS. 8 and 9, the splitter apparatuscomprises vertical supporting structure having a cross shaped base plate126 fixed to the Vupper ends thereof. Four cutter assembly supportplates 127 are slidably mounted for horizontal radial movement withrelation to the .axis of the splitter apparatus by means of L-shapedcross section guide members 130 fixed to the base 126. Each of theguides 130 has an inwardly projecting portion 131 which extends over itsrespective support plate 127 and retains the support plate between the`guides 130.

A threaded adjusting rod 132 is provided for radially adjusting theposition of each support plate 127and is rotatably mounted at one endupon the vertical supporting structure 125 and at the other end upon thebase 126 by means of suitable bearing elements 135 and 136 fixed to thestructure 125 and the base 126, respectively. The bearing elements 135and 136 include suitable means for retaining the rod 132 against axialmovement. At the outward end of each rod 132, there is fixed a crank 137for rotating the rod. Each of lthe support plates 127 has a dependingelement 140 fixed thereto and threadedly receiving the rod 132. It canbe appreciated that the support plate 127 may be adjusted as to radialposition by rotating the rod 132 by means of the crank 137. Normally,the support plate 127 will be adjusted for a particular type of par-tand will remain in the adjusted position until manufacture of that typeof part has been completed at which time the tooling of the splitterapparatus aswell as the positions of the 'support plates 127 areconverted over to a new par-t.

A cutter assembly 140 is mounted for radial horizontal movement uponeach of the support plates 127 by means of L-shaped cross section guides141 fixed to the support plates 127 and extending over the base plate143 of each cutter assembly.

A fluid motor 142 is fixed' to each support plate 127 and has its pistonrod `145 fixed to the base 143 of `the cutter assembly 140. Anvilstructure 146 is fixed to each of the cutter assembly base plates 143and extends upwardly therefrom. The anvil structure includes a diecarrier 147 and an anvil die 150 fixed to the outer surface of the diecarrier 147. Each anvil die 150has an outwardly facing die face 151shaped identically to that portion of the inner surface 152 of theworkpiece 155 which is adjacent to the area to be cut. In the center ofeach anvil die 151, there is an indentation 156 which extends thecomplete length of the die and has a shape corresponding to the cutterdie 157. Because the anvil die face 151 is shaped identically to theworkpiece, the anvil Vdie structure 146 is used to .position theworkpiece prior to the cutting operation. This positioning function isaccomplished by actuating the fluid cylinders 142 to retract theirpiston rods 145 and move the cutter assemblies 140 radially outwardlycausing the anvil faces 151 to engage the workpiece at the areas 152 andposition the workpiece for the cutting operation.

Each of the cutter assemblies further includes vertical side plates 160and a rear or outer vertical plate 161 all of which are fixed to .thebase plate 143 of the assembly and define a three-sided enclosure forthe cutter die structure 162. The cutter die structure includes a diecarrier 165 and the cutter die 157 fixed to the inner yface of the diecarrier. The cutter die structure 162 is guided for `radical horizontalmovement by means of the base 143, the side members 160 and a top member166 fixed to the side members 160 and the outer member v1611.

A cam member -167 is received between the outer member 161 and the diecarrier 165 and is guided for vertical movement by means of L-shapedguides 170 fixed to .the router 'member 161. 'Ihe cam member 167 has aT-shaped key 171 fixed to its cam face 172 and received within aT-shaped groove 175 in the cam face 176 of the die carrier 165. A iiuidmotor 177 is fixed to the base 143 of each cutter assembly y140 and hasits piston rod 180 fixed to the cam member 167. `It can be seen thatretraction and projection of the piston rod 180 will move the cam member167 vertically in opposite directions andl will move the die carrier 165radially inwardly and outwardly.

A latch element 181 is pivoted at 182 to the top member 166 of eachcutter assembly 140 and includes a pair of arms 185, each of which hasan indentation 186 receivable upon a pair of pins 187 which extendoppositely from each of the anvil structures 146. The latch element 181may be swung into and out of. engagement with the pins 187 by means offluid motors 190 each of which are pivoted at one end to the respectivetop members 166 land have their piston rods 191 pivoted to the latchelements 131.

Each of the cutter assemblies 140 has an inwardly projcting work piecesupport 192 Xed thereto. Each anvil die carrier 147 has a pair of bores200 within which are mounted pin guides 201 which slidably receive guidepins 202 fixed to the die carriers 4165. The pins 202 and guides '1insure that the dies -156 and 157 are maintained centered during thesplitting operation.

After the work piece has been dropped into the splitter apparatus andrests upon the work piece supports 192, the latching elements 181fmay beswung into engagement with the pins 187, thusl locking the upper ends ofeach anvil structure 146 against horizontal movement with respect Itorespective top members 166. Thus, the latchin-g elements 181 function toretain the anvil structures rigidly in position so that the cutter dies157 have arm back-up member against which to cut. After the latchingelements 181 have been properly secured .to the pins 187 and the anvils147 are moved outwardly to properly position the workpiece, the uidmotor -177 may be roperated to move the cam |167 of each cutter assemblydownwardly to cut the scrap areas 79 and to separate the eX- pandedparts 75-78 making up the Work piece 158. Preferably, the cutter dies157 and anvil dies 156 are each formed so that a pair of notches isproduced in each scrap portion 79, these notches assisting inpositioning the separated parts in their respective trim die apparatus.

After the parts have been thus separated, the cams r167 are'ra'ised byactuation of the fluid motors 177 and each of the cutter dies 157 isretracted outwardly away from the workpiece. The separated parts arethen free to be conveyed away upon the conveyors 120. The anvilstructures 146 are then moved inwardly by fluid motors 142 in readinessfor a further workpiece by actuation of the fluid motors 142.

From the above description, it will be evident that the lpresentinvention provides an improved process and -appared to toggle pressoperation wherein each stamping produces only a single part. It has alsobeen found that the present invention permits p-recise forming of partssuch as automobile doors and fenders and that this pre' ciseness greatlyexceeds anything known in conventional toggle press procedure,eliminates guesswork and per-mits formation of parts to very narrowtolerances.

While the invention has been disclosed and described in some detail inthe drawings and foregoing description, they are to be considered asillustrative and not restrict-ive in character, as modifications mayreadily suggest themselves to persons skilled in .this art and withinthe broad scope of the invention, reference being had to the appendedclaims.

As used in the following claims, the terms tubular and closed shape areintended to mean cylindrical and also to describe the rectangular shapeof FIG. 2 as well as other such shapes.

The invention claimed is:

1. Apparatus for forming a cluster of parts comprising a plurality ofdies each having an outwardly facing forming surface having an otherthan annular shape desired for one surface of a respective one of saidparts, each of said die forming surfaces including a plurality offorming portions adapted to engage the inside surface of an annularmember for the forming thereof, and means for moving said dies outwardlyaway from one another to stretch an annular member thereover, all of theforming portions of each respective forming surface being y lixed withrespect to the other forming portions of the respective forming surfacewhereby each forming surface retains the same shape throughout theforming process.

2. Apparatus for forming sheet metal parts comprising a plurality ofdies each having an outwardly facing forming surface having an otherthan annular shape desired for one complete surface of a respective oneof said parts, each of said die forming surfaces including a pluralityof forming portions adapted to engage the inside surface of an annularmember for the forming thereof, means for simultaneously moving saiddies outwardly to stretch an annular member thereover and form theparts, all of the forming portions of each respective forming surfacebeing Xed with respect to the other forming portions of the respectiveforming surface whereby each forming surface retains the same shapethroughout the forming process, and means for separating the thus formedparts.

3. Apparatus for forming a cluster of sheet metal parts comprising aplurality of dies each having an outwardly facing surface having theshape desired for the complete inner surface of a respective one of saidparts, a plurality of outer dies each having an inwardly facing surfaceincluding inwardly projecting portions having the shape desired forrecesses and indentations in the outer surface of a respective one ofsaid parts, and means for simultaneously moving said inner diesoutwardly to stretch an `annular member thereover and to force theannular member against said outer dies,

4. Apparatus for forming a cluster of sheet metal parts comprising aplurality of dies each having an outwardly facing surface having theshape desired for the complete inner surface of a respective one of saidparts, a plurality of outer dies each having an inwardly facing surfaceincluding inwardly projecting portions having the shape desired forrecesses and indentations in the outer surface of a respective one ofsaid parts, means for moving said outer dies inwardly and locking themin an inward position ready for forming of said parts, and means formoving said inner dies simultaneously outwardly to stretch an annularmember thereover and to force the annular member against said outerdies.

5. Apparatus for forming a cluster ofy sheet metal parts comprising abase, a plurality of inner dies slidably mounted on said base for radialmovement, a plurality of outer dies mounted radially outwardly of saidinner dies on said base for radial movement coaxial to said inner dies,a ring fixed to said base and surrounding said outer dies, cam meansreceived and axially movable between said ring and said outer dies andkeyed to said outer dies whereby axial movement of said cam meansproduces inward and outward radial movement of said outer dies, meansfor axially moving said cam means, a wedge-shaped inner driver. receivedinwardly of said inner dies for coaxial movement with respect thereto,said -inner driver being keyed to said inner dies whereby axial movementof said driver produces inward and outward radial movement of said innerdies7 and means for producing axial movement of said inner driver.

6. Apparatus for forming a cluster of sheet metal parts comprising abase, a plurality of inner dies slidably mounted on said `base forradial horizontal movement, a plurality of outer dies mounted radiallyoutwardly of said .inner dies on said base for radial horizontalmovement coaxial to said inner dies, a ring fixed to said base andsurrounding said outer dies, cam means received and axially movablebetween said ring and said outer dies and keyed to said outer dieswhereby axial movement of said cam means produces inward and outwardradial movement of said outer dies, means for vertically moving said cammeans, a wedge-shaped inner driver received inwardly of said inner diesfor coaxial movement with respect thereto, said inner driver being keyedto said inner dies whereby axial movement of said driver produces inwardand outward radial movement of said inner dies, means for producingaxial movement of said inner driver, said wedge-shaped driver having atapered portion engaging a cooperating tapered portion of each of saidinner dies, the taper of alternate ones of said engaging portions beinggreater than the taper of the other of said engaging portions wherebyalternate ones of said dies are drawn inwardly to a greater extent thanothers of said dies, the other of said dies having recesses on theirrearward faces which receive portions of the alternate ones of said dieswhereby the minimum circumference of the inner dies can be as small aspossible as compared to the distance across the forming faces of saiddies.

7. Apparatus for forming a cluster of allochiral `sheet metal partscomprising a plurality of dies having outwardly facing allochiralforming faces each having an other than annular shape desired for onesurface of a Y metal parts comprising a plurality of dies each having an-outwardly facing forming surface having an other than annuiar shapedesired for the complete inner surface of a respective one of saidparts, one of said dies having a forming face which is allochiral inrelation to the forming faces of another of said dies, each of said dieforming surfaces including a plurality of forming portions adapted toengage the inside surface of a tubular sheet metal member for theforming thereof, and means for moving said dies simultaneously outwardlyto stretch a tubular sheet metal member thereover, all of the formingportions of each respective `forming surface being fixed with respect tothe other forming portions of the respective forming surface wherebyeach forming surface retains the same shape throughout the formingprocess.

9. Apparatus for, forming a cluster of sheet metal parts comprising aplurality of dies each having an outwardly facing forming surface havingan other than annular shape desired for one complete surface of arespective one of vsaid parts, said dies being movable from a retractedposition wherein the dies are adjacent one another to an expandedposition wherein the dies are spaced from one another, each of said dieforming surfaces including a plurality of forming portions adapted toengage the inside surface of an annular member for the forming thereof,and means for moving'said dies from said retracted to said expandedposition whereby an annular member can be stretched over said dies withsaid die faces forming individual parts therein and the portions of saidmember at the spaces between said dies being stretched to form scrapconnecting said individual parts, all of the forming portions of eachrespective forming surface 'being fixed with respect to the otherforming portions of the respective forming surface whereby each formingsurface retains the same shape throughout the forming process.

1t?. Apparatus for forming a cluster of sheet metal parts comprising aplurality of inner dies each having an outwardly facing forming surfacehaving the shape desired for one complete surface of a respective one ofsaid parts, said inner dies being movable from a retracted positionwherein the dies are adjacent one anotherv to an expanded positionwherein the dies are spaced from one another, a plurality of outer dieshaving inwardly facing forming surfaces including inwardly projectingportions having the shape desired for recesses and indentations in theouter surface of said parts, means for moving said outer dies inwardlyland locking them in an inward position ready for forming of said parts,and means for moving said inner dies from said retracted to saidexpanded position whereby a tubular sheet metal member can be stretchedover said dies with said inner die forming `faces forming individualparts therein and the portions of said member at the spaces between saidinner dies being stretched to form scrap connecting said individualparts. I

References Cited by the Examiner UNTED STATES PATENTS 7/1934 Ireland113-118 9/ 1963 Seeloff 72-393

1. APPARATUS FOR FORMING A CLUSTER OF PARTS COMPRISING A PLURALITY OFDIES EACH HAVING AN OUTWARDLY FACING FORMING SURFACE HAVING AN OTHERTHAN ANNULAR SHAPE DESIRED FOR ONE SURFACE OF A RESPECTIVE ONE OF SAIDPARTS, EACH OF SAID DIE FORMING SURFACES INCLUDING A PLURALITY OFFORMING PORTIONS ADAPTED TO ENGAGE THE INSIDE SURFACE OF AN ANNULARMEMBER FOR THE FORMING THERETO, AND MEANS FOR MOVING SAID DIES OUTWARDLYAWAY FROM ONE ANOTHER TO STRETCH AN ANNULAR MEMBER THEREOVER, ALL OF THEFORMING PORTIONS OF EACH RESPECTIVE FORMING SURFACE BEING FIXED WITHRESPECT TO THE OTHER FORMING PORTIONS OF THE REPECTIVE FORMING SURFACEWHEREBY EACH FORMING SURFACE RETAINS THE SAME SHAPED THROUGHOUT THEFORMING PORCESS.